Checkout ladder #262 climbs from 40 to 119 in five steps — 40, 50, 69, 89 and 119 — with three darts per finish and a double to end on.
40 is a straight double: D20. If the dart lands in the single by mistake you are left on 20, which still has a double finish with the darts you have left. 50 is a straight double: Bull. A miss into the single leaves an odd number, so the next dart has to set up a double before you can finish.
69 is a two-dart finish: T19 D6. 89 is a two-dart finish: T19 D16. 119 needs all three darts: T20 19 D20. If the first dart misses its treble, the board will show the new route straight away.
One route here finishes on the bull (Bull for 50); it counts as a double.
At best the five finishes need 9 darts out of 15. Your result counts the finishes you make first and the darts you used second. These are friendly numbers. Aim at the inside half of the double on the first dart — a miss on that side lands in the single and keeps the finish alive.